How much does a new boiler cost in Northern Ireland?

Why we don't list a price on this page

Boiler installs across Northern Ireland vary on at least eight independent factors. List a range, and we'd either have to make it so wide it's useless ("between £2,000 and £6,000"), or pick a narrow band that's wrong for most properties.

Worse: a low headline number anchors the conversation downwards. You start asking why your quote is higher than the website said. The honest answer is "your house is different from the imaginary one we put on the page", but at that point we've already lost trust.

So we don't list one. We agree the price on the phone, after a thirty-minute home survey, and the quote is fixed once it's written. Below is what shapes that number, in plain terms.

Eight things that move the price

1. 01 Boiler type. Combi, system or regular. The choice depends on bathroom count and incoming flow rate, not on what's cheapest. A combi in a property that needs a system boiler is a false economy that costs you on hot-water performance for ten years.
2. 02 Property era and pipework state. Victorian terraces with microbore primaries cost more than 1990s estates with modern 15mm/22mm copper. Back-boiler-to-combi conversions in 1970s NIHE-era stock cost more again, because the chimney pipework needs capping and the gas supply rerouting.
3. 03 Mains pressure and flue route. NI Water mains pressure varies by elevation across Belfast, Lisburn and the rural fringe. A combi specified without a flow-rate test is wrong. External flue routing on a mid-terrace or in a conservation area can need rerouting that adds half a day of labour.
4. 04 Network. Phoenix Natural Gas across Greater Belfast, Firmus Energy across Lisburn, Antrim, Newtownards and Coleraine, SGN across the rural west. Each network has its own connection process and timeline; oil-to-gas conversions on Firmus add 4-8 weeks of scheduling that doesn't apply on Phoenix.
5. 05 Brand and warranty length. Worcester Greenstar, Vaillant ecoTEC and Ideal Logic Max are the three flagship ranges with 10-year warranties. Mid-tier ranges have 5-7 year warranties at lower price points. The right choice depends on the install, not the brochure.
6. 06 What the install actually includes. A magnetic filter on every install, full chemical flush where the manufacturer requires, Building Control notification, Gas Safe certificate, warranty registration. Skipping any of these makes the headline price look cheaper, but the install is going to cost you in year three when the warranty refuses to honour a claim.
7. 07 Existing system upgrade scope. New thermostats, smart controls, replacement radiators, rebalancing, pressurisation conversion. Each is optional but each shifts the number meaningfully.
8. 08 Conservation area or listed-building consent. Most installs aren't affected. Belfast's BT9 Malone, Stranmillis, Cliftonville, Laganbank and Fort William; Lisburn's Market Square, Castle Street and Bow Street; and a handful of listed buildings change the flue routing and sometimes need consent. Adds time, not always cost.

The six questions to ask every quote

You're going to get three quotes. The £-numbers will differ. The questions below will tell you why, and which quote is actually comparable.

1. 01 Who lodges Building Control? Should be the installer, lodged within ten days of commissioning. If it's on you, it's a price-corner cut.
2. 02 Is the magnetic filter included? Should be standard on every install. If it's an optional add-on, walk.
3. 03 What's the system flush spec? Chemical flush is included as standard if the manufacturer requires it. A power flush on a heavily sludged system is separate. Either should be specified, not assumed.
4. 04 Who registers the manufacturer warranty? Should be the installer, on the day of commissioning. Self-registration is fine but a sign the installer hasn't fitted that brand much.
5. 05 Will my flue route work? Should be confirmed at survey. 'We'll figure it out on the day' is how installs end up overrunning by two days.
6. 06 What's the labour warranty? Manufacturer covers parts; installer covers labour and workmanship. Two years on the labour is a reasonable minimum.

Why "the cheapest quote" is rarely the cheapest install

Cheapest installs in 2026 are the ones that cost you twice in 2030. Common shortcuts that show up as a £200-£500 saving up front:

• No magnetic filter fitted, system sludges within five years.
• No chemical flush, manufacturer warranty refuses pressure-loss claim in year four.
• Building Control notification not lodged, you find out at sale-conveyance.
• Flue position not properly checked, install overruns by a day, you pay the labour.
• Boiler size based on rule-of-thumb, not measured flow-rate, hot water underperforms.

A proper install is more expensive on day one because it's actually a complete install. The price difference is usually 8-15% across credible installers fitting the same boiler. The differences in process and inclusion are where the gap lives, not in the boiler model.

Grants and finance

Manufacturer-backed finance is available on most installs (Worcester, Vaillant, Ideal). The Northern Ireland Sustainable Energy Programme (NISEP) and BoilerCare grants apply to eligible households for some installs; eligibility depends on benefits status and current heating type. We'd flag both at the survey rather than promote them as a sales angle.

Full guide to boiler grants in Northern Ireland

What we'd recommend

Get three quotes. Use the six questions above to compare them. Pick the installer who can answer all six without hedging, even if they're not the cheapest. A boiler is a fifteen-year asset; the £200 you saved on year-one labour is going to look small when the diverter valve fails outside warranty in year six.

And if you'd rather just get a survey from us: we'll give you a fixed-price written quote within twenty-four hours of the survey, with all six questions answered up front in writing.